Messages in this thread | | | Date | Fri, 22 Aug 2008 08:05:20 +0200 | From | Ingo Molnar <> | Subject | Re: patch "x86: MOVE PCI IO ECS code to x86/pci" breaks CPU hotplug |
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* Robert Richter <robert.richter@amd.com> wrote:
> On 21.08.08 15:02:59, Ingo Molnar wrote: > > > > * Jan Beulich <jbeulich@novell.com> wrote: > > > > > Converting __cpuinit functions called out of init_amd() (and similar > > > others) to __init (and making them subject of xxx_initcall() handling > > > isn't valid, as they would no longer be called for hot plugged CPUs. > > > > > > Further, since it's likely that in virtualized environments the MSR > > > write would at best be ignored, I'd also recommend using the > > > fault-safe accessors here *and* check that the bit actually got set > > > before setting PCI_HAS_IO_ECS (one would obviously have to BUG() when > > > hot-plugged CPUs fail to set the bit when those available at boot > > > successfully did so). > > > > hm, which patch is this exactly, and in what tree? It's not upstream nor > > in -tip. > > Probably this in the mainline kernel is meant: > > commit 3a27dd1ce5de08e21e0266ddf00e6f1f843bfe8b > Author: Robert Richter <robert.richter@amd.com> > Date: Thu Jun 12 20:19:23 2008 +0200 > > x86: Move PCI IO ECS code to x86/pci > > "Form follows function". Code is now where it belongs to. > > Signed-off-by: Robert Richter <robert.richter@amd.com> > Signed-off-by: Ingo Molnar <mingo@elte.hu> > > The problem is code like this: > > +static int __init enable_pci_io_ecs(void) > +{ > + /* assume all cpus from fam10h have IO ECS */ > + if (boot_cpu_data.x86 < 0x10) > + return 0; > + on_each_cpu(enable_pci_io_ecs_per_cpu, NULL, 1, 1); > + pci_probe |= PCI_HAS_IO_ECS; > + return 0; > +} > > It is only called during the setup and if the cpu is enabled. I intend > to rewrite the cpu setup code using cpu notifiers.
ok. Unfortunately the revert looks quite non-trivial for v2.6.27. Could we have some _really_ minimal fix for v2.6.27?
Ingo
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